My Geography teacher has started an experiment which involves me writing about what I have learnt in my lessons and about any geographical news that interests me. My Geography teacher is also going to write a blog about what she teaches me (and therefore what I should have learnt!) and hopefully the two blogs will match up. The idea is that this will not only help me to consolidate what I learn but that it will also help fellow students do the same and keep up to date with current issues.

Wednesday, 7 March 2012

Where would the British be without the Gulf Stream!?

Hello everyone! Hopefully everyone is enjoying the new climate module! Millie has written a very useful and succinct summary (something I never manage to achieve!) post on all the basics we have covered so far so there is no point me doing it to......instead I am going to write a little about the ocean circulation. After a polite reminder that Geography is the study of peoples interaction with the environment I am going to focus on the impact that the Gulf Stream has had on our development and the way society functions; projecting this into the future to examine how we would cope without it; rather than focusing on the science (although this is incredibly interesting, for the exam, unfortunaltely we do not seem to need to know that much - however feel free to ask lots of questions as this links with my EPQ topic).
I will get the sciency bit out of the way first....

This is a graphic I produced as part of my EPQ and so perhaps goes into a little two

much detail but the image in the top left hand corner illustrates really well the role of the

Gulf Stream in heat transfer

- Continents divide the oceans up into basins and so this complicates the direction of currents which are already inlfluenced by Coriolis in the same way as winds

- Gyres (large circular) form and move clockwise in the Northern Hemisphere

- Currents are driven by winds, Coriolis and the sinking of cool water near the Poles

- Antarctic Cirumpolar Current is the only current that goes right the way around Earth, preventing icebergs from entering the oceans - this is important when analysising possible threats capable of perturbing the ocean circulation

- Gulf Stream is initiated as water moves across the Atlantic from Africa to the Carribean. As it travels close to the Equator is gets heated. It then gets deflected by landmasses, Coriolis and other factors and so flows along the Florida coast. As it reaches higher latitudes it gets colder and saltier (we say salinity increases) as when ice forms, salt is removed from the fresh water and left behind in the ocean (brine rejection). This makes it more dense so it sinks.

- The Gulf Stream is a surface current but there are also other currents than flow deeper in the oceans. Together they connect all of the world's oceans, transporting heat, and forming the Global Conveyor Belt

I will get into trouble if I talk anymore about the theory but just a quick mention for the deep water circulation (just ignore the next paragraph if you don't want to know anything more than we strictly need to - the bit after is very relevant though)......

Another graphic I made for my EPQ - atleast they are coming
in handy!

All the currents are linked in a complicated way and are dependent on each other. The sinking of Gulf Stream waters at high latitudes, feeds the crucial Thermohaline Cirulation (THC). Due to the combination of high evaporative salt enrichment
and Gulf Stream presence, THC is best developed in the Atlantic. The Gulf
Stream transports warm, salty water to the north-east of the Atlantic where it
cools, mixing with the cold Arctic Ocean waters. This causes it to become dense
enough to sink, both to the south and east of Greenland. The resulting current
is part of a larger system that connects the North Atlantic to the rest of the
Atlantic, Indian, Pacific and Southern Ocean, where the two main sinking
regions spread out in the subsurface ocean, thereby able to influence the
world’s oceans from depths of 1000m and below, before the cold, dense water gradually warms and returns to the
surface. Basically, the Global Conveyor Belt consists of surface and subsurface
currents, sinking regions and return waters which interlink to form a closed
loop. The conveyor starts in the Atlantic where salty water proceeds northwards
to Iceland, is thermally densified, and thus sinks through the interior to form
the conveyor’s lower limb.There are also deep-water flows such as the North Atlantic Deep Water (NADW), which have great influence on our lives. THC is very important. THC engages the
entire ocean into the climate system by permitting ocean water to directly
interact with the atmosphere (over a timescale of 100-1000
years), ergo, via the Gulf Stream and NADW, moderates the UK’s climate – one
that is, consequently, on average, 5°C
warmer than countries of similar latitude. On a more global scale, THC
influences biome distribution, NPP, sea level, ITCZ movement and productivity
of oceans whilst individual currents themselves allowed for the early
navigation of the oceans, thus aided development. However, the present pattern
has not always existed and is vulnerable to many external factors and cyclic atmospheric
changes. Even a significant weakening would have multiple detrimental impacts,
with the effects being globally experienced and, as the oceans control the
Earth’s climate over decades to centuries, understanding how they are likely to
change is crucial in selecting how to appropriately mitigate and adapt to
future climate change.

Why is the Gulf Stream important for the UK?

Raises air temperatures, thereby helping to deliver mild winters and cool summers to the British Isles. The warmer waters have a significant impact on North Atlantic temperatures as they give up about one-third of the energy they had previously stored from the sun. The extent of the warmth provided by the Gulf Stream can be seen by comparing the climate of countries at a similar latitude to Britain's - i.e Canada which is a bit colder! It is believed that the UK climate is 5°C warmer than it would be without the Gulf Stream. Warming effect of Gulf Stream prescence enabled agricultral productivity to increase, permitting an acclerated transition through the early stages of the Rostow Model of Development.

Perhaps the easiest way to understand the benefits of having the Gulf Stream nearby is to summarise the impacts on society if it was absent. Whilst there are many extrinsic forcing factors capable of shutdowning THC, thereby causing a southward shift or even complete shutdown of the Gulf Stream, the most likely is a large freshwater input at high latitudes due to melting ice, consequential to global climate change.........

How would the UK cope without the Gulf Stream?

This area is currently recieving a lot of attention (this is what I focused on when at the Met Office) and model simulations suggest that freshwater forcing of a shutdown, as a result of global climate change, could cause:

- 8C cooling

- Increase in wind speed

- Precipitation reduction

- Storms tending further north so hitting UK with increasing frequency

- 1-2 months additional snow cover

- 80cm sea level rise

- 2% reduction in the UK's GDP

Sea level rise is potentially worrying for the UK as factoring in isostatic readjustment, population growth forcing more onto marginal lands and £130 billion worth of assets currently at risk of coastal flodding, greater than 10% as present, of our coastline would need to be protected. Even factoring in global climate change, the UK would still see reduced precipitation and 3C reduction in temperature. Increased snow cover would drastically decrease mobility, isolate people from an alrady straioned health care amongst other amenities, instigate higher living costs due to restrictions on agriculutre and issues with transporting food (in 2010 one milk company had to throw away 100,000 litres of milk) and cause huge disruption to education (altough, I don't think us students would mind a few more snow days!!!). Lower temperature and prolonged snow cover could cause issues for the UK's ageing population, with 1/4 in the southwest unable to heat their homes, possibly initiating greater urbanisation with cities able to offer facilities in close proximity, more likely to recieve greater funding for protection and the urban heat island effect warming, on average, summar and winter by 5C and 2C respectively. Consequently, a shift in employment could be experienced, with construction work becoming more seasonal and people looking for office-based work that can be completed from home during winter moths. Restricted agricultural and inducstrial productivity, fewer TNC's attracted whose presence stimulats cumulative causation and reduced touristic value, amongst other factors, is projected to generate a 2% reduction in the UK's GDP (-0.1% of global economy) with politicians put under increasing pressure to develop effective contingency plans to prevent societal collapse during protracted snow cover, minimise economci impacts and provide sufficient protection in coastal areas.

Global Impacts???

The two hemispheres and the atmosphere and oceans are coupled in a way we don't need to understand but this means that, despite centralisation of impacts in the North Atlantic, impacts would be globally experienced. A 1C temperature increase in projected in the Southern Hemisphere, which would only be accentuated by global warming. A southward shift in the ITCZ would occur, reducing monsoon intensity/duration over India - worrying as India's water security is already poor, their rivers are reliant on glaciers, sea-level is threatening to displace millions thus increasing population density and India's population is expected to exceed China's by 2030. A 5% reduction in global NPP would be accompanied by alterations in temperate biome distribution and ecosystem disruption whilst with 20% of the world's fisheries dependent on upwelling systems and risng SST's futher reducing ocea oxygen content, food scarity would become prevalent especially with the global population soaring to 9 billion by 2045.

As you might have guessed, I find all of this stuff really interesting but I get the impression all you really need to know is the basic's of the Gulf Stream formation, a bit about how it has helped the UK and, just that society would struggle to sustain current livestyles without it - so hopefully this all made sense!

4 comments:

Thanks, I think it is a very interesting topic although the possibility of a future thermohaline circulation is a worrying one!!! Once I start my degree I will be able to write about this a lot more, and in more detail which may be of interest to you to!

Geography Films

My Geography teacher is always reminding my class that watching (geography related) films can contribute to the 3 hours of reading time we are supposed to do each week. On both her blog and the Facebook page there are lists of recommended films and so I thought I would start to watch some of them and write a review on them from a student's perspective. If I would recommeded them to a fellow student then I will add the film to my own list below.......

- THE AGE OF STUPID (great film to watch for the energy module as it talks about climate change, energy consumption and production via some interesting case studies)

- THE COVE (this film is very thought provoking and presented the issues surrounding the dolphin trade - before watching this I didn't know a lot about the issue, especially the scale of it in Japan, and it left me feeling very shocked that something like this still exists today in such a developed country)

-ENCOUNTERS AT THE END OF THE WORLD (a great documentary with some simply stunning footage and interesting interviews that collectively provide an insight into life in Antarctica and the important research that is taking place)

-THE CONSTANT GARDENER (a rather sad story about how a drug company exploit the Kenyan population to allow them to test a new drug, despite the fact they know it has harmful side effects - good film for development and globalisation)

- ERIN BROCKOVICH (a good film that presents the negative impacts of the natural gas industry and the extent to which large companies are prepared to go to, to cover this up)

- SLUMDOG MILLIONAIRE (provides an insight into the life of children living in the Indian slums - good film to watch for development)

- GANDHI (a biopic about the life of Gandhi with particular reference to his prominent role in India's struggle for freedom from colonial rule)

- CRY FREEDOM (set in South Africa and tells the true story of Biko and his friendship with a white liberal newspaper editor - good film to watch for development)

- THE PAINTED VEIL (set in China, in the 1920's, and explores the impact of a cholera outbreak on a village, including references as to how religious beliefs make containing cholera even more challenging)

- BLOOD DIAMOND (set amid the explosive civil war overtaking 1999 Sierra Leone; it explores many issues including those surrounding the diamond trade, supply of arms to rebels and child soldiers - good film to watch for development and globalisation module)- THE DAY AFTER TOMORROW (after the Larsen B ice shelf collapses, the thermohaline circulation shutdowns, provoking glacial inception in the northern hemisphere - a good film to watch and then point out the geographical/scientific mistakes!)

- GOODBYE BAFANA (follows the unlikely friendship that forms between Mandela and his prision officer - good for development and globalisation)

- INVICTUS (after 27 years imprisionment, Mandela becomes South Africa's first elected president and this film follows his bid to unite the country via the rugby world cup - good film for development and globalisation)

- DARFUR (a group of international journalists travel to a village in Darfur in search of evidence to persuade the UN that genocide has occured but are forced to live after the Janjaweed turn up and threaten to kill them.... a film to watch for either development and globalisation or the population module but be warned it is very graphic)

Geography Books

I am a bit of a bookworm and often prefer reading a good book to watching a film and so (like I am doing with the Geography films) I am going to read some of the suggested books and write a review on them so I can comment on whether or not I think they are worth reading........

- AN INCONVENIENT TRUTH, Al Gore ( presents the issue of climate change and discusses how it has been caused and the impacts it is likely to have - well worth reading but if you prefer the film version is equally as a good)

- OUR CHOICE, Al Gore (this books follows on from An Inconvenient Truth by offering the solutions Al Gore thinks are required to solve the issue of Global Climate Change)

- THE BOY WHO HARNESSED THE WIND, William Kamkwamba and Bryan Mealer (tells the extraordinary true story of a Malawian teenager who overcame many obstacles to provide electricity and clean water for his village by capturing the energy in both the wind and the sun)

- BLOOD RIVER, Tim Butcher (tells the story of Tim Butchers quest to retrace the journey taken by H.M.Stanley in the 1870's. From this you get an insight into the history of the Congo and the factors that have effected its development - great book for the development and globalisation module as it provides an insight into the impact colonialism has had on Africa)

- GAIA, James Lovelock (presents the Gaia hypothesis which is the idea that the Earth functions as a living organism and so self-regulates to adapt to changing conditions - puts forward some very interesting ideas and really makes you think - it is worth a read!)

- THE REVENGE OF GAIA, James Lovelock (applies the Gaia hypothesis to global climate change - again an intriguing read which presents some interesting ideas and solutions to problems we are likely to face)

About Me

Whilst studying A-levels in Geography, Chemistry, Biology, Maths and History, I became completely fascinated by the Earth Sciences and found them particularly good for feeding my natural curiosity, providing answers to my never ending list of questions! Despite my relentless enthusiasm and frequent question asking, I was quite a quiet student in comparison to the rest of my class so my teacher asked me to start this blog as part of her experiment to test the benefits of incorporating social media into education. The aim was to find out if social networking can be a valuable educational tool and discover how much I actually learnt in lessons. It proved to be a huge success, for both myself and other students, with all my A-level notes still available for students use. I am currently at University studying BSc (Joint Honours) ‘Physical Geography with Oceanography’ and still asking way too many questions! In an attempt to continue to share my love for anything Earth Science-related, and to see if it can have the same benefits at Higher Education, I am trying to continue the blogging and use of social networking. I hope it proves to be a useful and interesting read!

The what, why and how of this blog.......

Hopefully you will have worked this out by now, but this blog is written from a student's perspective and, when combined with my teachers blog, should provide an insight into what I get taught - therefore what I should have learnt - in my Geography lessons. The idea is that this will make it a useful place to go to consolidate your learning; somewhere to go if you didn't quite understand something or missed a lesson. As well as this, posts will be written on anything of general geographical interest whether that be something currently in the news, anything related that I read or watch, anything I do or a topic that I just fancy finding out more about - all of this is designed to broaden our geographical knowledge. When it comes to revision I will try and write up as many notes as possible but it is unlikely that I will be able to cover everything so just let me know if there is anything you would like me to cover. So, thats what the blog is about (simply sharing, with anyone willing to read it, lots of geographical stuff that interests me!) and I am writing it because I tend to get a little enthusiastic about Geography and ask too many questions and so by channeling my interest in this way it will hopefully help you as much as it helps me!!! Whats the best way to use it? Well for starts reading/following the blogs and other resources is the only way you will benefit from them! Secondly, participate and get involved - comment on things, I am bound to get things wrong so correct me, you won't agree with everything I say so tell me what you think and perhaps even suggest things for me to read, watch or look into as I am always looking for new ways to extend my knowledge outside of the classroom. Geography is a discursive subject and, especially with human Geography, for the most part about forming/expressing opinions, so discuss the topics raised via the blogs etc. - trust me, its an easy way to learn!

I am now at University studying BSc (Joint Honours) Physical Geography with Oceanography - to keep my A-level notes separate I have started a new blog for current news and what I am learning in University - anything relevant I will also post on this blog, but please feel free to ask questions or requests posts! I hope students are still finding this a useful resource!

Disclaimer

'What I learnt in Geography this week.....' was created by, with content written by Vicki The Geography Student as part of an experiment conducted by Millie The Geography Teacher.

All posts published are my personal views, apart from where stated otherwise, and not those of the college I attended, my University or associated partners